Organic hydrocarbon compounds can be dehydrogenated efficiently by contacting these compounds in the vapor phase in the presence of a free oxygen-containing gas with a catalyst comprising at least one element of the iron group consisting of nickel, cobalt and iron in association with tin, phosphorus and at least one alkali metal and oxygen. By this process, various unsaturated hydrocarbons such as butene, butadiene, isoprene, etc., can be produced from hydrocarbon feedstocks having at least one ##STR1## grouping. While this process constitutes an important improvement over the earlier procedures for the production of unsaturated hydrocarbon compounds, it remains desirable to increase the yield and selectivity of this process.